Form class limits the size of the form to be not larger then the screen size. It is done in Form SetBondsCore override and unfortunately cannot be changed. To be precise it is limited by the size in
SystemInformation.MaxWindowTrackSize. For the latter, one can read in MSDN :
"...The value returned by MaxWindowTrackSize refers to dimensions of the entire desktop. The user cannot drag the window frame to a size larger than these dimensions. A Form can override this value by overriding the MaximumSize property..."
One can set Form MaximumSize to be smaller, but not larger than MaxWindowTrackSize.
I hope this helps. Should you have any other questions, feel free to ask.
the Telerik team